Polymer/glass or polymer/ceramic composites are known to exhibit superior characteristics compared to non-composite polymer or glass, or ceramic materials taken individually. Improved characteristics include but are not limited to increased thermal stability, chemical stability, and enhanced fracture toughness. This combination of characteristics has made polymer/glass composite materials suitable for uses including but not limited to use as fire retardants. Other uses include but are not limited to lightweight structural applications; for example, optical windows and protective coatings.
The polymer/glass composites are made in two forms. The first form is a glass-phase dispersed material within a polymer carrier matrix material phase as shown by W. A. Bahn and C. J. Quinn, MICROSTRUCTURES OF LOW MELTING TEMPERATURE GLASS/POLYARYLETHERKETONE BLENDS, Preprints, Apr. 5-9, 1991, ANTEC'91, 2730, and the second form is a polymer-phase dispersed material intercalated throughout a glass carrier matrix material phase as demonstrated by E. J. A. Pope et al., TRANSPARENT SILICA GEL-PMMA COMPOSITES, J. Mat. Res. Soc., 1989 4(4), 1018. In either form, the microstructure of either or both phases persists as the phases are mixed. In other words, there exist discernible bulk phases or islands of dispersed material within the carrier matrix material of the composite.
Either form of these bulk phase polymer/glass composites is made by thermomechanical bulk mixing or diffusion processes. Generally, one or both bulk phase composite constituents are heated and softened, or melted at temperatures ranging from about 380.degree. C. to about 430.degree. C., then mechanically mixed and kneaded at the elevated temperature as taught, for example, by W. A. Bahn et al. Alternatively, a polymer solution may be passed through a porous glass/ceramic matrix leaving the polymer entrained on the pore surfaces as demonstrated by E. J. A. Pope et al.
While bulk phase polymer/glass composites prepared in these ways exhibit the improved properties discussed above, it is believed that the molecular phase glass/polymer composites of the present invention exhibit further improvement in these properties. Moreover, it is expected that the composite material of the present invention will extend performance limits of glass/polymer composites.
The method of making the molecular phase glass/polymer composites requires lower temperatures than the methods for mechanical mixing of bulk phase glass/polymer composites.